In recent years, a transparent resin plate is increasingly demanded, in place of an inorganic glass plate hitherto, as a window material for vehicles such as automobiles and window glass for building material attached to architectures such as houses, buildings and the like. In particular, for the vehicles such automobiles and the like, it is proposed to use a transparent resin plate for the window material for reduction in weight, and an aromatic polycarbonate-based transparent resin plate is especially excellent in fracture resistance, transparency, light weight, easy workability and so on, and its use as a promising window material for vehicle is under consideration. However, such a transparent resin plate has a problem in abrasion resistance and weather resistance in use in place of the inorganic glass plate.
Hence, for the purpose of improving the abrasion resistance and the weather resistance of the transparent resin plate, it is proposed to use various hard coating materials, in particular, a silicone-based hard coating material to form a coating film, namely, a hard coating layer on the surface of the transparent resin plate. Further, it is also proposed to provide a primer layer on the transparent resin plate in order to improve the adhesiveness between the hard coating layer and the transparent resin plate at that time. A method for forming the hard coating film composed of the hard coating layer and the primer layer is generally a two-coating method of a wet method of sequentially applying liquid compositions for forming the respective layers on the transparent resin substrate and drying them.
On the other hand, because the two-coating method of sequentially applying the respective layers and drying them is low in productivity in the method for forming the hard coating film composed of the hard coating layer and the primer layer on the transparent substrate, Patent Reference 1 (JP-A 2006-035519) discloses a method for manufacturing a resin substrate with a hard coating layer with good productivity by forming the primer layer on a polycarbonate resin film by coextrusion, and injection-molding a polycarbonate resin substrate on the surface on the opposite side to the primer layer of the resin film.
However, the method in Patent Reference 1 has such a problem that though the productivity is improved, the weather resistance is sacrificed because the physical property of the resin constituting the primer layer is made suitable for molding by coextrusion. Hence, a method for manufacturing a resin substrate with a hard coating layer with good productivity while sufficiently keeping the adhesiveness and the weather resistance in a resin substrate with a hard coating layer to be obtained is hoped for.